The ballast weight you carry doesn't change during a dive, but it's often the biggest problem for divers who struggle with perfecting neutral buoyancy. Many divers are overweighted for the type of diving they do, carrying more lead than they need. That makes buoyancy control more difficult because every extra pound of lead has to be balanced with an extra pound of buoyancy. 

But because the air in your BC expands and contracts with depth changes, you have to be constantly adding or subtracting air from your BC. So extra lead means extra thrust up or down when you change depth, and requires extra fiddling with your BC valve controls. Sometimes it means nearly constant fiddling.

Here are our tips for taking off that extra weight.

Just do it. Take off two pounds before your next dive. Can't get below the surface? Before you reach for the lead again, make sure you really need it. Getting below the surface, especially on the first dive of the day, can be surprisingly difficult and can trick you into carrying more lead than you really need. 

Be patient. The plush lining of a dry wetsuit can trap a surprising amount of air, and therefore buoyancy, in its fibers, and it takes a minute or so to get fully wet.

Reach up. Hold the inflator hose over your head and stretch it upward a little so its attachment point to your BC is highest. At the same time, says Linda Van Velson, a PADI course director, "dip your right shoulder and squeeze the BC against your chest with your right arm." This maneuver encourages the last few bubbles to find the exit.

Rock backward a little. Many BCs trap a bubble of air just behind your head. Rocking backward as if you are in a La-Z-Boy recliner moves the exhaust hose over the bubble and lets it escape.

Relax. Many of us move our hands and feet more than we realize, especially at the beginning of the dive. To counteract that, hold your right arm still at your side (your left is holding up your exhaust hose), extend your legs and point your fins straight down so they have the least resistance to sinking.

Exhale. Another tendency is to hold your breath, and a lungful of air adds as much as 10 pounds of buoyancy. Exhale and hold it until you start sinking, then take shallow inhales until you get below five feet.

Force it. Another option is to use your body weight to generate some downward momentum by lifting part of it out of the water, then letting it fall back. Lying on your face, jackknife your upper body downward, then lift one leg, then another, out of the water. The weight of your legs will drive you downward, and once your fins are in the water you can kick down.

Use the line. If the dive boat is tied off at a mooring, use the line to help pull yourself down. This trick also works for divers who need to go down slowly to equalize. 

Get a little help from your friends. Ask your buddy to gently tug your fin and pull you down for the first few feet of your descent. Usually, by the time you're in 10 to 15 feet of water, you should sink without help.

What's the ideal amount of weight? Use our Buoyancy Calculator to determine what's right for you.

Read our Tips on Neutral Buoyancy for more secrets on achieving a the feeling of weightlessness underwater.

A leaky mask has got to be the most annoying thing a diver has to  deal with when trying to enjoy a dive (with a fogged-up mask coming in a close second). So any extra effort you can invest in the dive store fitting a new mask to your face is definitely time well spent. 

However, the standard dry-fit procedure of centering the mask on your face, making sure all skirt edges are in contact with your skin, then inhaling gently —without the strap attached — to see whether you can get an airtight seal, won’t necessarily guarantee that you’re going to have a leak-proof dive. While some lucky divers are able to put their masks on and hit the water and never touch their mask for the entire dive, for most of us, getting our mask fully sealed takes a little finesse. We've got some tips to avoid those annoying leaks:

• After giant-striding into the water and popping to the surface, take a moment to remove your mask, give your head a good double-dunking, and hand-squeegee your hair back and away from your face. Then, position the mask on your face before stretching the strap over your head. If you’re wearing a hood, you can forgo the hair step as long as no renegade strands are sticking out. But run a finger around the edge of the hood opening to make sure the mask skirt is against your skin and not overlapping the neoprene.

• Double-check to make sure the mask is properly centered on your face. If it’s not, you probably will break the seal once you start diving. Also, double-check the position of the strap on the back of your head. If it it's too high, it tends to lift the bottom of the skirt; if too low, it affects the top of the skirt. If it's too tight, it can distort the shape of the skirt — that can break the seal too. 

• Just before descending, push the mask lens inward, forcing some air out and creating a good air pressure seal. Now you’re ready for your descent. Once under water, if the seal is sound, water pressure should take over and you should be good to go. At some point, you’ll probably want to nose-blow a little air back in to avoid getting mask squeeze as you go deeper.

By following these steps, hopefully you’ll be able to pull off a dive without having to contend with water constantly seeping — or gushing — into the mask. If not, you might want to consider investing in a purge mask. 

There's no denying that peak performance buoyancy control separates the dive paddlers from the pros. When all the big talk is over and the water closes over your head, there is nothing that pulls the whole scuba diving thing together like perfect buoyancy control. 

The secret is pinpoint buoyancy control, and it all begins with fine-tuning your weighting — that's how much lead you thread on your belt or put into your pouches. If you are carrying just the right amount of weight, you will have the smallest amount of BC inflation. That means less drag and more efficient finning. Less BC inflation also means less buoyancy shift with depth, so you'll make fewer adjustments. There are many tricks, but pinpoint buoyancy control is the fundamental skill. Precise control of your buoyancy is what enables you to hover completely motionless and fin through the water, at any depth, without using your hands at all.

It sounds easy, so why isn't it?

In fact, pinpoint buoyancy control requires getting more than one thing right. 

The factors that affect your buoyancy besides ballast weight are BC inflation, your trim, exposure suit, depth and breath control. Your ballast weight and your trim are the only two factors that, once you've selected them, stay put. All the others are variables, changing during the dive along with time or depth or both. Some you can control, some you can't. 

Here is our advice for getting perfect neutral buoyancy so you can enjoy your time underwater without fiddling too much with your BC inflator hose.

Take a course. PADI offers a course in buoyancy and weighting called "Peak Performance Buoyancy." The course teaches precise buoyancy control, streamlining, weight and trim adjustment, equipment configuration options and relaxation techniques. 

Pre-dive preparation. Real buoyancy control begins, as does any dive, with pre-dive preparation. As you pack and check your equipment, double-check to make sure nothing has changed that could affect initial weighting. New wetsuit? Major factor. Nice, springy wetsuits need more weight than old rancid flatties. A fresh suit has more inherent buoyancy at first because diving, especially deep diving, simply bursts its bubbles. New BC? Unlikely to have a major effect at this point, but it will in the water. New weight belt? Maybe a nifty new shot belt? Take a moment to make sure the new compares well to the old. Stick 'em on a bathroom scale; often there is variation between claimed and actual weight. New cylinder? Another biggie. Some cylinders are negatively buoyant when full and simply less negative when empty; others sink first and float later.

Do a buoyancy check. Here's how to make a proper buoyancy check: With your lungs half-full, you should float at eye level with no air in your BC. But the fact that your average cylinder loses about 5 pounds as it empties gets you thinking about the buoyancy change in a tank and is a good reminder that it's best to do a buoyancy check with a nearly empty cylinder before you dive. This is obviously a bit of a pain, so add about 5 pounds to your weight if you have done your buoyancy check with a full one. You can always take a moment and recheck buoyancy after a dive, just before you get out of the water. See our Buoyancy Calculator  for more tips on being properly weighted. If you you're overweighted because you struggle with descents, read How To Take Off Weights for tips on getting down without adding weights.

During the dive. Now for the dive itself. Understand why feet-first descents have many advantages: One is that it's easiest to completely empty your BCD in this position. Double-check that the point where the deflator hose attaches to the bladder is really the closest point to the surface as you prepare to descend. It's often helpful to dip your opposite shoulder. Exhale, and if you're properly weighted, you should sink slowly. Keep your hand on the BC inflator and get ready to add controlled bursts of air to adjust your descent rate. You'll add more as the descent continues. If you're making a deep dive for the first time, it can be a bit of a surprise to see just how much air you have to add as you continue. During the dive, enjoy the fruits of your labor. Concentrate on what happens as you breathe. If you see something interesting below you, exhale and drift down for a look. Inhale and you'll level off and start to rise. Don't vary your breathing habits too much, though; breathing slowly deeply and continuously is of primary importance. 

During the ascent. Keep the point about BC positioning in mind while making gradual ascents too. It's easy to trap some air in an unfamiliar BC, which will continue to expand as you ascend. On deeper dives, and given neutral buoyancy, you should only have to start swimming up a little before expanding air takes over. Make sure you're ready to vent this off as needed.

Make the safety stop count. The goal is to be neutral while doing your end-of-dive safety stop, so that's when you can really fine-tune your buoyancy. As you near the surface, stop at 15 feet. After three minutes, kick slowly for the surface. If you have done everything right, there should be no air in your BCD as you break the surface. You should also now be floating at eye level, rising a little as you inhale and sinking slowly as you exhale. If this is not the case, make appropriate adjustments before your next dive.

Log it. After each dive, write down what exposure suit you wore, what equipment you used, how much lead you carried, how much your body weighs and whether you seemed too heavy or light at your safety stop.

SALT WATER VS. FRESH WATER WEIGHTING

If most of your diving is done in freshwater springs or lakes, then ballast calculations should be done in freshwater. If you dive mostly in the ocean, then do the calculations in saltwater. If you switch back and forth, you’ll need to adjust your ballast needs as you go. Be prepared to add anywhere from 4 to 7 pounds going from fresh to saltwater.

uvenile loggerhead turtles swim into oncoming ocean currents, instead of passively drifting with them, according to a study published August 6, 2014 in the open-access journal PLOS ONE by Donald Kobayashi from National Oceanic and Atmospheric Administration and colleagues.

A Florida family scavenging for sunken treasure on a shipwreck has found the missing piece of a 300-year-old gold filigree necklace sacred to Spanish priests, officials said on Tuesday.

Eric Schmitt, a professional salvager, was scavenging with his parents when he found the crumpled, square-shaped ornament on a leisure trip to hunt for artifacts in the wreckage of a convoy of 11 ships that sank in 1715 during a hurricane off central Florida's east coast.

After the discovery last month, a team of Spanish historians realized the piece fit together with another artifact recovered 25 years ago. It formed an accessory called a pyx, worn on a chain around a high priest's neck to carry the communion host. The dollar value is uncertain.

"It's priceless, unique, one of a kind," said Brent Brisben, operations manager for Queens Jewels, which owns rights to the wreckage, located in 15-foot (4.5-meter) deep Atlantic Ocean waters.

Schmitt, who lives near Orlando, last year discovered about $300,000 worth of gold coins and chains from the same wreckage, Brisben said. Schmitt's parents have hunted for sunken treasure as a hobby for a decade.

By law, the treasure will be placed into the custody of the U.S. District Court in South Florida, Brisben said. The state of Florida may take possession of up to 20 percent of the find. The rest will be split evenly between Brisben's company and the Schmitt family.